Generally, a display comprises an array substrate, thin film transistors (TFTs) are disposed on the array substrate and are arranged in a matrix, each of the TFTs functions as a switch to connect a data line with a pixel, the time period of turning-on and -off is controlled by a gate line. Taking a liquid crystal display as an example, the array substrate of the liquid crystal display comprises a plurality of gate lines and a plurality of data lines intercrossing vertically and longitudinally with each other. The gate lines and the data lines define a plurality of pixel units, for instance, each pixel unit comprises a TFT and a pixel electrode, for instance, a gate electrode of the TFT is electrically connected with the gate line, a source electrode of the TFT is electrically connected with the data line, and a drain electrode of the TFT is electrically connected with the pixel electrode.
At present, a metal oxide TFT attracts wide attention due to the advantages such as high carrier mobility, good homogeneity, transparency, simple manufacturing process and etc. An etch stop metal oxide TFT is a common type of metal oxide TFT, the manufacturing process thereof is simple, an etch stop layer formed on a metal oxide active layer can protect the metal oxide active layer from being damaged in the procedure of forming source/drain electrodes, so as to improve performance of the metal oxide TFT.
According to a position relationship between the gate electrode and the active layer, the metal oxide TFT can comprise a bottom-gate structure and a top-gate structure, namely, in the bottom-gate structure, the gate electrode is located under the active layer, in the top-gate structure, and the gate electrode is located on the active layer. In addition, in the top-gate structure, a light-shading metal layer is disposed under the metal oxide active layer to protect the metal oxide active layer from light.